Fender BXR 200 Service Manual - Parts List
BXR 200
Transistors Q11, Q12, and associated components comprise the Current Limiting or Short Proof protection
circuit. There are usually two conditions which demand excessive output current from the amplifier. A
shorted speaker cable, or a load impedance which is below the minimum rating of the amplifier. If these
conditions occur, the voltage drops across the Emitter Resistors (.33
Ω
5 Watt) will dramatically increase.
On the positive side of the amplifier, C11 charges through R29 & R34. On the negative side C12 charges
through R30 & R35. Htis will cause Q11 & Q12 to turn on. This limits the amount of signal which is
available to the Base of the Driver Transistors (Q13 & Q14). CR20-CR23 make up a latching circuit that
senses the signal through R22. This ensures that Q11 & Q12 turn on hard in conduction. When the fault
condition is removed from the output, the current limiting circuit will remain latched up until the input signal is
removed.
Q13 & Q14 are the Driver Transistors for the output section. Q15-Q18 are the output transistors. Notice on
the schematic that the Base resistors carry the “Fp” designation. Htis indicates a Flame Proof/Fuse Type
resistor. They won’t burn and they act like a fuse when exposed to an over-current condition. This prevents
catastrophic damage to the output section. If an output transistor shorts Base to Collector or Base to
Emitter, the resistor will simply open. IN many cases the amplifier will continue to operate, but at a reduced
power level. An increase in distortion may also become apparent. When replacing these resistors,
ALWAYS use the Fuse Type OEM part.
PARTS LIST
NOTE: SHADED ITEMS ARE FOR REFERENCE ONLY
PREAMP PRINTED CIRCUIT BOARD ASSEMBLY
QTY PART # DESCRIPTION REFERENCE DESIGNATION
5
048451000
BUTTON PUSH OFF WHITE
@S1-S5
1
033379000
CABLE RIBBON 3 CKT 10”
@P3B
1
049334000
CABLE RIBBON 3 CKT 20”
@P4B
1
048914000
CABLE RIBBON 8 CKT 7”
@P1B
1
048845000
CABLE RIBBON 12 CKT 3-3/4”
@P7B
1
033605000
CAP AE RDL .15uF 50V 20%
C75
1
038689001
CAP AE AX .47uF 100V
C8
2
028458000
CAP AE RDL 1uF 50V 20%
C68,72
4
026517001
CAP AE AX 2.2uF 50V
C4,16,42,45
12
038692001
CAP AE AX 10uF 35V
C9,18,21,24,27,30,33,36,39,41,48,51
2
028456000
CAP AE RDL 22uF 25V 20%
C63,81
1
028471000
CAP AE RDL 47uF 50V 20%
C59
1
028479000
CAP AE RDL 220uF 25V 20%
C70
1
038873001
CAP CA 22PF 100V LL
C5
1
004026000
CAP CD 22PF 1000V 10%
C69
3
038698001
CAP CA 47PF 100V 10%
C3,58,80
1
007029000
CAP CD 220PF 1000V 10%
C67
1
039264001
CAP CA 1500PF 100V LL
C15
4
038703001
CAP CA .1uF 50V LL
C43,44,83,84
1
027278000
CAP MPF .1uF 63V 10%
C60
2
027280000
CAP MPF .15uF 63V
C13,14
1
027281000
CAP MPF .22uF 63V
C82
2
030933000
CAP PFF .0012uF 50V 5%
C46,47
2
033579000
CAP PFF RDL .0015uF 100V 10%
C65,71
2
030936000
CAP PFF .0022uF 50V 5%
C37,38
2
030939000
CAP PFF .0039uF 50V 5%
C34,35
2
033582000
CAP PFF RDL .0039uF 100V 10%
C61,66
1
033583000
CAP PFF RDL .0047uF 100V 10%
C62